Improvement in concrete pavements



WILLIAM GILBERT. 1

improvement in Concrete Pavements.

N0. 125,284, Patented Apr\2,1872.

UNITED STATES PATENT QFFICE.

IMPROVEMENT IN CONCRETE PAVEMENTS.

Specification forming part of Letters Patent No. 125,284, dated April 2, 1872.

`To whom it may concern:

Be it known that I, WILLIAM GILBERT, of

Detroit, in the countT of Wayne and Statey of Michigan, have invented a new and useful Improvement in Paveinents; and I do declare that the following is a true and accurate description thereof, reference being had to the aeconlpanying drawing and to the letters of reference marked thereon and being a part of this specification, in which- Figure lis a perspective of a section of my pavement. Fig. 2 is a vertical section on line a and bin Fig. 1.

The nature of this invention relates to a pavement composed of coal-tar, gravel, wood, and sand, wherein the coal-tar is so treated with air-slaked lime as to form a pliable elastic gum.

This invention consists in the construction of a pavement wherein wooden blocks arranged in rows are laid down with a gravel and cement composition prepared in a peculiar manner upon a foundation of sand placed above the boards, or wooden foundation, as is more fully hereinafter described.

Take three (3) parts distilled coal-tar, heat ed until it is liquid, and thenvslowly stir in one part of dry or airfslaked lime, which neutralizes the sul phuric, carbolic, and other acids in the coal-tar, and neutralizes or drives off all the easilyvolatilizcd constituents of said coal-tar, forming a compound which will remain semi-elastic under the influence of the atmosphere.

For the purpose of making a pavement, at'- ter forming a proper foundation by layinga wooden foundation on a bed of sand, and covering the boards with sand to the uniform depth of two inches, the above compound, mixed with gravel, is poured over the foundation or between the vertical strips of board placed across the street. For the purpose of mixing the above compound with the gravel it must be heated until it is soft, and then poured over the gravel so that each and every stone will be coated with the compound. The gravel should be sifted so as to be clear of all sand or loa-m, and heated enough to prevent the compound from cooling before the stones are coated. When the gravel so coated is placed on the road-bed it should be rolled or rammed down smooth, which will cause the narrow blocks set up across the street to sink into the sand about an inch.

In the accompanylng drawing, A represents the board foundation, which should be placed on a sand or other smooth bed. E is two inches of sand resting on the board founda- Witnesses:

MYRoN H. CHURCH, PATRICK F. BARRY. 

